Donald Trump and Theresa May have had their first phone conversation since his victory in the US election was announced.
In the conversation, Trump invited May to visit him as soon as possible and they affirmed the "special relationship" between the two countries.
The duo discussed a desire to strengthen trade and investment ties, a Number 10 source said, which could be significant as the UK hopes to strike deals around the world after leaving the European Union.
A Downing Street spokesman said: "The Prime Minister spoke to US President-elect Donald Trump earlier this afternoon to congratulate him on his hard-fought election campaign and victory.
"The president-elect said he very much looked forward to working with the Prime Minister and congratulated her on her recent appointment. The Prime Minister and President-elect Trump agreed that the US-UK relationship was very important and very special, and that building on this would be a priority for them both.
"President-elect Trump set out his close and personal connections with, and warmth for, the UK. He said he was confident that the special relationship would go from strength to strength.
"The Prime Minister expressed her commitment to building and expanding the UK's relationships around the world, particularly after the referendum vote, and the importance of our partnership with the US.
"She noted President-elect Trump's commitment in his acceptance speech to uniting people across America, which she said is a task we all need to focus on globally.
"The Prime Minister said that we have a long history of shared values and added that she looked forward to that continuing in the future. She highlighted her wish to strengthen bilateral trade and investment with the US as we leave the EU.
"But she said that our relationship is so much more than that and our two countries have always stood together as close allies when it counts the most. President-elect Trump strongly agreed and added that the UK is a 'very, very special place for me and for our country'. The call ended with President-elect Trump inviting the Prime Minister to visit him as soon as possible."
Trump had talks with a series of world leaders including Ireland's Enda Kenny before speaking to May, but ministers insisted the "special relationship" remained intact.
The call did not happen until 1.45pm and Chancellor Philip Hammond suggested it may have been because there was "no urgent business" for the pair to discuss.